Injector coil fuse blows when crank

Hello,

Your vehicle keeps blowing the fuse because there is a short to ground in the circuit[s] that that fuse is protecting. This happens because of Ohm's Law, the laws that govern electricity in a vehicle. Ohm's law states that if one of the three properties of electricity stays constant, and one always is in an automotive circuit [Voltage-there is constant battery voltage] and one of the remaining two goes down[Resistance-resistance goes to zero as the electricity has a direct path back to the negative battery terminal] than the last property must go up proportionally [Amperage-Amperage will go to the Amperage rating of the battery]. The Amperage/Current or the flow of electricity will overtake the fuses amperage rating and "pop" the fuse blows, protecting the circuit, just like it was designed to do. In the diagrams down below I have included a wiring diagram of your vehicle's Coil On Plug circuits and a guide on how to find short to grounds in an automotive electrical circuit. You will need to use a Digital Multi-meter [DMM] to do go through this guide. Here is a link below explaining how to use one, if needed:

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Please go through these guides and get back to with what you are able to find out.

Thanks,
Alex
2CarPros

There's no ground wires in the injector or ignition coil circuits, so if you grounded something, that would be what is shorted. Both circuits are grounded by the Engine Computer. It switches the grounds on for the injectors to pulse them for a few milliseconds, and it switches the grounds off for the ignition coils, individually, when they need to create the spark.

The first diagram has fuse # 24 circled. That feeds circuit F42 dark green / light green for the six injectors. The two circuits are continued on the second diagram at call outs "I" and "J". This is the circuit that has to be shorted for that fuse to blow.

If you aren't sure if the short is something you caused, another way to find this is to replace the blowing fuse with a light bulb. That will limit current flow in the circuit to safe value, and give you a visual indication of when the short is present or removed. Normally I stick a 3057 brake light bulb in place of the fuse, but for anything related to the automatic shutdown, (ASD) relay, which this is, it's better to bypass the relay instead because that relay only gets turned on for one second when you turn on the ignition switch. Obviously that is not enough time to do any testing. The relay gets turned on again during engine rotation, (cranking or running), but since the engine doesn't run, any testing would have to be done while a helper is cranking the engine. Again, not practical.

The way to do this is to install a good fuse into socket #24. Don't turn the ignition switch on or that fuse will blow again. Now, remove the ASD relay, then stick in two universal crimp-type spade terminals into the socket's terminals 30 and 87. That's if you have the common 1" cube relays. If you have the skinnier relay like the one shown on the right of the drawing, use the two terminals the arrows are pointing to.

Use a pair of small jumper wires to connect those two terminals to the light bulb. A 3057 brake light bulb has easily accessible terminals and will limit current to one amp. It can get pretty hot when it's at full brightness, so be careful where you lay the bulb.

By connecting the bulb across the relay socket, the circuit will be energized all the time. No need to turn the ignition switch on, and there won't be nearly enough current to blow the new fuse. If the short is present, the bulb will be full brightness. Now you can move wire harnesses around, unplug things, and disconnect connectors to see what removes the short from the circuit. When you find something that removes the short, the bulb will get dim or go out completely.

I just noticed they changed the relay terminal numbering, but the physical locations are the same. Use terminals 82 and 84. Two small red arrows are pointing to them in the fourth diagram.

Hello again,

No. The f42 wire is a hot wire coming from the ASD Relay pin 30, or possibly pin 87 and is the wire supplying power to the component to be power[Coil[s]]. It should not be grounded. This is your short to ground.

Thanks,
Alex
2CarPros

There's no capacitors, diodes, or ground connections in those circuits. Can you post some photos of what you're working with?

Hello,

Okay, this looks like an Radio/Ignition Capacitor for collecting the Electro-Magnetic Frequency[EMF] from the ignition coils and storing it then releasing it to ground of the vehicle battery. When your coils release the electricity that is built up in the winding's of the coil to produce the electricity to make the spark plugs spark, it creates a collapsing magnet pulse that gives of EMF and will be picked up by any unshielded wiring. So it is the job of these capacitors to collect and disseminate the EMF to the vehicle's ground. A good example of what happens when these capacitors aren't working is if you have ever accelerated in a vehicle and the more you accelerated the louder a whining hum would come over the vehicle's speakers, that hum is the EMF from the ignition coils being collected by the speaker wires instead of the capacitor.

Thanks,
Alex
2CarPros

Hello again,

Here are the wiring diagrams with the positive wires to the Coil On Plugs[COP][s] and fuel injectors and the capacitors highlighted for you in the diagrams down below. I hope this helps.

Thanks,
Alex
2CarPros

Hello again,

Where is the wire originating from? If you know.

Thanks,
Alex
2CarPros

Hello again,

Okay, in the diagrams down below I have sent the entire set of ground distribution wiring diagrams from the vehicle manufacturer. I hope that this helps.

Thanks,
Alex
2CarPros